Sect. A: Inorganic, Bio-inorganic, Physical, Theoretical
& Analytical

The studies cover a large number of conformations
generated theoretically over the wide range of apical angles between angular
to linear shapes. The results demonstrate that, similar to the bonding in
diborane, there are two equivalent three-centered bonds in ozone embracing
three oxygen atoms in all the conformations.

2008

Investigation
of microstructure of glycidyl methacrylate/methyl acrylate copolymers by 1D
and 2D-NMR spectroscopy.

The copolymers of glycidyl methacrylate/methyl
acrylate have been synthesized by solution polymerisation using benzene as
solvent and benzoylperoxide as an initiator. The Distortionless Enhancement
by Polarization Transfer, 13C-1H heteronuclear single
quantum coherence and Total Correlation Spectroscopy have been used for the
complete spectral assignment of 13C and 1H-NMR spectra.

2017

Volumetric properties of binary mixtures of some n-alkoxyethanols with 2-pyrrolidinone
and N-methyl-2-pyrrolidinone at 298.15 K

The excess molar volumes for binary liquid mixtures
ofn-alkoxyethanol + 2-pyrrolidinone
or N-methyl-2-pyrrolidinone have been measured with a continuous dilution
dilatometer. In all mixtures the excess molar volumes are negative across the
entire composition range. In each case the excess molar volumes decrease as
the alkyl chain length of the alkoxyethanol increases while it increases from
2-pyrrolidinone to N-methyl-2-pyrroli-dinone.

2025

Voltammetric studies of an
oxazolone derivative of cefaclor in aqueous buffers

Relative viscosities of some mineral salts viz;
sulphates of sodium, potassium/ammonium and magnesium, at different
concentrations have been determined in binary aqueous solutions of urea at
different temperatures. The sulphates of ammonium and magnesium behave as
structure breakers whereas sodium and potassium sulphate act as structure
makers in the present system.

2039

A study of activation
parameters for viscous flow process of some tetraalkylammonium salts in
binary mixtures of N, N–dimethyl-formamide
and ethyl methyl ketone

Notes

A topological method is described for prediction
of 13C NMR chemical shifts of alkanes and cycloalkanes using PI
index. Some good results are obtained when the cycloalkanes are classified
into low, middle and high ring-size.

Synthesis
of [{(acac)2Ru}2(m-L)] and
[{(bipy)(acac)Ru}2(m-L)] has been achieved by the reaction of dipotassium
salt of 2,5-dihydroxy-1,4-benzoquinone) with two equivalents of cis-[RuIII(acac)2(CH3CN)2]
or [RuIIBr(acac)(bipy)].

A localized molecular orbital study of
the structure and bonding of ozone

Dulal C Ghosh* & Arindam Chakraborty

The localized molecular orbital theory and
energy partitioning formalism have been invoked to study the structure and
bonding in ozone molecule. The range of investigation covers a large number of
conformations generated theoretically over the wide range of apical angles
between angular (C2v) to
linear (D¥h)
shapes. The results demonstrate that, similar to the bonding in diborane, there
are two equivalent three-centered bonds in ozone embracing three oxygen atoms
in all the conformations. The possibility of a triangular structure of ozone is
ruled out because the computed localized molecular orbitals demonstrate that
there is no bonding between the terminal oxygen atoms and the decomposed energy
components show that the interaction between terminal oxygen atoms is strongly
repulsive. Charge density distribution is asymmetric in the homonuclear
molecule and its dipole moment is an algebraic sum of bond moment and lone pair
moment and lone pair on the apical oxygen atom contributes significantly to the
dipole moment. It is demonstrated that any attempt of calculating the apical
angle from the experimentally determined dipole moment would be erroneous and
misleading. Variation of dipole moment as a function of angular to linear
reorganization of molecular shape is correlated in terms of computed quantum
mechanical hybridization of the lone pair on the apical oxygen atom. The
barrier to inversion of ozone through the linear (D¥h) transition state originates
from a subtle interplay of one- and two- center energy components over the
entire skeleton of the molecule.

The copolymers of glycidyl methacrylate/methyl
acrylate (G/M) have been synthesized by solution polymerisation using benzene
as solvent and benzoylperoxide as an initiator. The 1H-NMR
spectroscopy has been used to determine the copolymer compositions. The
comonomer reactivity ratios have been determined by Kelen- Tudos (KT) and
non-linear least squares error in variable method (EVM) and are found to be rG
= 4.03 ± 0.7, rM = 0.45 ± 0.07 and rG=4.6, rM = 0.49, respectively. The
Distortionless Enhancement by Polarization Transfer (DEPT), 13C-1H
heteronuclear single quantum coherence (HSQC) and Total Correlation Spectroscopy
(TOCSY) were used for the complete spectral assignment of 13C and
1H-NMR spectra.

Volumetric properties of binary
mixtures of some n-alkoxyethanols with2-pyrrolidinone and
N-methyl-2-pyrrolidinone at 298.15 K

Amalendu Pal*, Anil Kumar &Harsh Kumar

The excess molar volumes (VE) for binary liquid mixtures of (n-alkoxyethanol + 2-pyrrolidinone or N-methyl-2-pyrrolidinone) have
been measured with a continuous dilution dilatometer at 298.15 K and
atmospheric pressure as a function of composition. The alkoxyethanols are
2-methoxyethanol (CH3OCH2CH2OH),
2-ethoxyethanol (C2H5OCH2CH2OH),
and 2-butoxyethanol (C4H9OCH2CH2OH).
In all mixtures the excess molar volumes are negative across the entire
composition range. In each case the excess molar volumes decrease as the alkyl
chain length of the alkoxyethanol increases while it increases from
2-pyrrolidinone to N-methyl-2-pyrrolidinone. The results have been used to estimate
the excess partial molar volumes of the components. The change of VE and with composition and
the number of alkyl chain-length in the alkoxyethanol molecule is discussed
with a view to understand some of the molecular interactions present in
alkoxyethanol-cyclic amide mixtures.

Voltammetric studies of
an oxazolone derivative of cefaclor in aqueous buffers

Bhim Bali Prasad*, Sandeep Gupta & Shouri Banerjee

Electrochemical properties of cefaclor at a mercury
electrode in aqueous solution of varying pH
have been studied through tast, pulse (normal and differential), and cyclic
voltammetric techniques. For this, the electroinactive cefaclor is transformed
into electroactive penicillenate analogue ‘oxazolone derivative’ under strong
acidic hydrolysis condition. The derived oxazolone system underwent two-steps
irreversible reductions involving proton-participations (2e-, H+;
4e-, 4H+) when voltammograms scannedcathodically. However, in cyclic
voltammetry, a typical wave due to sulphhydryl group oxidation is noticed on
scan reversal in anodic direction. The results have been discussed by taking
into account the implications of reactant and product adsorptions onto
electrode surface during the course of reductions.

A study on viscosity
B–coefficient of some mineral salts in binary aqueous solutions of urea at
various temperatures

M L Parmar*, D K Dhiman
& R C Thakur

Relative viscosities of some
mineral salts viz; sodium sulphate, potassium sulphate, ammonium sulphate and
magnesium sulphate, at different concentrations have been determined in binary
aqueous solutions of urea (mole-fractions of urea, Xurea= 0.010, 0.025, 0.040, 0.055 and
0.070) at 308.15K and in Xurea= 0.025 at different temperatures.The data have been evaluated using Jones-Dole equation and the obtained
parameters are interpreted in terms of ion-ion and ion-solvent
interactions.The activation parameters
of viscous flow have been obtained which throw light on the mechanism of
viscous flow.Ammonium sulphate and
magnesium sulphate behave as structure breakers whereas sodium sulphate and
potassium sulphate act as structure makers/promoters in the present system.

Viscosities and densities of tetrabutylammoniumtetraphenylammonium
boride (Bu4NBPh4), tetrabutylammonium bromide (Bu4NBr),
tetrapentylammonium bromide (Pen4NBr), tetrahexylammonium iodide
(Hex4NI), sodium tetraphenyl boride (NaBPh4) and sodium
iodide (NaI) in ethyl methyl ketone (EMK), N, N-dimethyl formamide (DMF)
and EMK+DMF solvent mixtures containing 0, 20, 40, 60, 80 and 100 mol % of EMK
in the concentration range (0.02 – 0.1) mol dm-3 at 25, 35, and 45oC
have been reported. The viscosity data have been analyzed in terms of A- and B-
viscosity coefficients of the Jones–Dole equation. Both A- and B–coefficients
have been found to be positive over the entire solvent composition range at all
temperatures. The B-coefficients have been resolvedinto B± ionic coefficients using Bu4NBPh4
assumptions. The B± values of tetraalkylammonium
ions are found to be positive. Partial molal volumes (Vo2)
have also been calculated which have been used along with B- values to
calculate activation parameters for viscous flow process of electrolytic
solutions. The activation parameters have been examined as a function of
solvent composition to interpret the solution behaviour of these
tetraalkylammonium salts in EMK-DMF mixtures.

A series of homobinuclear CoII, NiII,
CuII and ZnII complexes of the form [M2(Cl)xL](H2O)y
have been synthesized, where L is the deprotonated form of a new acyclic ligand
resulting from the Schiff base condensation of one mol of 2,6-diformyl-p-cresol and two moles of triazoles
(4-amino-3-methyl-1,2,4-triazole-5-thione; 3-methylsulphydryl-4-amino-5-mercapto
1,2,4-triazole and 3,5 dimercapto-4-amino-1,2,4-triazole) and characterized by
spectral, magnetic, thermal and redox properties. Cryomagnetic investigations
(79-296 K) reveal a strong antiferromagnetic spin-exchange between the copper
(II) ions (J based on H = -2 J Ŝ1. Ŝ2.is 260 cm-1).
The copper complex (CuII-CuII) oxidizes at a relatively
low potential (+0.55 V vs saturated
calomel electrode) leading to the formation of the corresponding CuIII-CuIII
complex. The EPR spectra of the copper complexes indicate an isotropic or
axially elongated or exchange coupled local molecular environment around the
metal ion. All compounds including the ligands are antimicrobially active.

Silyl-nitrogen compounds: Part
XIII—Reactions of metal halides
with silylated tosylhydrazines

S K Vasisht*, P Venugopalan, Jyoti Kataria & Anuradha
Sharma

Bis(trimethylsilyl)tosylhydrazine (Me3Si)2TsN2H
reacts with ECln (E=Al,Sn,Sb or Ti) to liberate Me3SiCl
and in the process form tosylhydrazides, ECln-1(Me3Si)TsN2H.
These compounds decompose on heating in
vacuo to form a variety of azane derivatives with the loss of volatile
products like Me3SiCl, HCl or SbCl3. Ditosyltetrazene
intermediate decomposes into ditosylhydrazine whose structure is determined by
X-ray diffraction.

Reactivity of [{(h6-p-cymene)RuCl(m-Cl)}2] towards some N-heterocyclics and tertiary
phosphines

Sarangapani M & Ravinder V*

Reactions of [{(h6-p-cymene)RuCl(m-Cl)}2]
with anthranilic acid (aa), pyrazole, 3-methylpyrazole, 3,5-dimethylpyrazole,
indazole, imidazole, benzimida-zole and tertiary phosphines have been carried
out to give complexes with the formula [(h6-p-cymene)Ru(aa)Cl], [(h6-p-cymene)Ru(aa)L] and [(h6-p-cymene)-Ru(aa)L¢]BF4.
The anthranilic acid behaves in a chelating bidentate N,O-bonded mode. Further,
chloride substitution takes place with azole derivatives and tertiary
phosphines to produce the neutral and cationic complexes, respectively. The
complexes have been characterised on the basis of elemental analyses,
conductance measurements, IR, 1H, 13C and 31P-NMR
and electronic spectral data and probable structures have been proposed. Redox
behavior of these complexes was also studied by cyclic voltammograms. An
irreversible single reduction wave for Ru(II) to Ru(0) ranging from –0.5 - –1.4
volts has been observed, which indicates a single step two electron process.

A topological method is described for
prediction of 13C NMR chemical shifts (å13Cn)of alkanes and cycloalkanes using
recently introduced PI (Padmakar- Ivan) index and to establish relative
potential of PI index compared to Wiener (W) and Szeged (Sz) indices.
Regression analysis of the data shows that in the case of alkanes the PI index
gives somewhat better results than W, whereas in the case of cycloalkanes
neither PI nor W nor Sz are applicable. However, excellent results are obtained
when the cycloalkanes are classified into low, middle, and high ring-size.

Preparation and unusual absorptionproperties of a ferrocene ended
2,6-bis-stilbazonium salt

Saumitra Sengupta* & Subir Kumar Sadhukhan

A 2,6-bis(ferrocenylvinyl)pyridinium salt, despite having a meta-orientation of the two
ferrocenylvinyl groups, shows a significant bathochromic shift compared to a
2-(ferrocenylvinyl)-pyridinium salt. This unusual phenomenon is explained
through participation of a cationic extended conjugated pathway present in the
resonance forms of the former.

Synthesis and characterization of some novel 4-formyl
pyrazolylthiazoles of potential medicinal interest using Vilsmeier-Haack
reaction

Pawan K Sharma*,
Karan Singh, S N Dhawan & S P Singh

Two series of 4-formyl-1,3-disubstituted pyrazoles namely
2-[3-(2,4-difluorophenyl)-4-formylpyrazol-1-yl]-6-substituted benzothiazoles (3)and 2-[3-(2,4-difluorophenyl)-4-formylpyrazol-1-yl]-4-arylthiazoles (7)have been synthesized for evaluation of their antifungal activity through
Vilsmeier-Haack reaction on hydrazones (2,6)
of 2,4-difluoroacetophenone with 2-hydrazino-6-substituted benzothiazoles (2) and 2-hydrazino-4-phenyl/substituted
phenylthiazoles (6). None of the
compounds exhibit any significant antifungal activity.

Synthesis and characterization of
dinuclear ruthenium(II) and ruthenium(III) acetyl-acetonato complexes with
dianion of 2,5-dihydroxy-1,4-benzoquinone as bridging ligand

Akhilesh K Gupta*, Anupama
Gupta & Anuradha Choudhury

Synthesis of
[{(acac)2Ru}2(m-L)] and [{(bipy)(acac)Ru}2(m-L)]
(where acac=acetylacetonato, bipy=2,2¢-bipyridine) has been
achieved by the reaction of K2L (where K2L=dipotassium
salt of 2,5-dihydroxy-1,4-benzoquinone) with two equivalents of cis-[RuIII(acac)2(CH3CN)2]
or [RuIIBr(acac)(bipy)]. The complexes have been characterized on
the basis of elemental analyses, magnetic susceptibility and conductivity data,
IR, UV-visible and 1H NMR spectral data and cyclic voltammetric
studies.

Silyl-nitrogen compounds: Part XIV—Reactivity of tetrasila-
phospha-tetrazene towards some group (IV) derivatives

S K Vasisht*, B N Anand & Km Usha Johal

Tetrasila-2-phospha-1-tetrazene
(Ms3Si)2N-N(SiMe3)-P=NSiMe3
is oxidized by CBr4 into [tris(trimethylsilyl)hydrazino]
[(trimethylsilyl)imino] (dibromo) phosphorane which lose Me3SiBr, on
heating in vacuum, to form [bis (trimethylsilyl)-hydrazino][trimethylsilylimino]
(bromo)phosphorane. Carbon disulphide forms a [1+2]-cycloadduct, which
decomposes at 60°C/10-3 torr back into its
reactants. Dichlorodimethylsilane and tetrachlorosilane behave similarly to
form diaza-phospha-sila-cyclobutane derivatives, whereas, the latter also form
a spirobicyclic derivative. All these compounds have been characterised.

Synthesis and characterization of mixed
ligand complexes of Cu(II), Ni(II) and Co(II) with cytidine and amino acids

P Rabindra Reddy* & A Mohan Reddy

The mixed ligand complexes of Cu(II),
Ni(II) and Co(II) with cytidine and amino acids, l-alanine, l-phenylalanine
and l-tryptophan have been
synthesized and characterized by elemental analysis, conductivity, Infrared
spectra, electronic spectral data and magnetic susceptibility measurements. In
these complexes, the nucleoside acts as a monodentate ligand involving only
N(3) in metal coordination whereas the amino acids acts as bidentate ligands
coordinating through carboxylate oxygen and amino nitrogen. A distorted
octahedral geometry for Cu(II), and octahedral geometries for both Ni(II) and
Co(II) was proposed.

Multiple equilibrium studies by pH-metric and visible spectral measurements in the ternary
nickel(II) complexes with 6-amino-penicillanic acid (6apa) as ligand A and
diamines [1,2-diaminopropane(dp), and 1,3-diaminopropane(tp)] and
diamino-carboxylic acids [ dl-2,3-diaminopropionic
acid(dapa), dl-2,4-diaminobutyric
acid(daba) and dl-2,5-diaminovaleric
acid(dava)] as ligands B show the presence of NiABH2, NiABH or NiAB
ternary complex species. The ligand, 6apa binds the metal ion via 6 amino and 7
carbonyl oxygen atoms in both the NiABH and NiAB species, and the binding of
ligand B in NiAB complexes is exactly similar to their binding in the
respective binary species. The results indicate the site of protonation in the
NiABH species to be with the terminal amino group of the ligand B. In the NiABH2
complexes, one proton is attached to the ligand A and other to the ligand
B. The computer simulated distribution of the complexes in solution has been
evaluated.

Ni(II)-8Hq terephthalate and Cu(II)-8Hq terephthalate
complexes have been synthesised and characterized by elemental analysis,
magnetic measurements, IR spectra and UV- Vis-spectra. The complexes have also
been analysed thermogravimetrically for the evaluation of their decomposition
kinetic parameters. The thermal decomposition of the compounds occurs mainly in
two steps. Kinetic parameters, (E*,Z and
DS*)
have been determined by using three different methods.

Photooxidation of
substituted purines in presence of peroxydisulphate in aqueous solution

Midudhula Sudha Swaraga& Mundra Adinarayana*

Photooxidation of
purine bases, viz., caffeine, theobromine, theophylline, xanthine,
hypoxanthine, adenine and guanine in aqueous solution has been carried out in
presence of peroxydisulphate (PDS). Peroxydisulphate is activated to SO4·-at 254 nm. The reactions are
followed by measuring the absorbance of purine bases at their respective lmax.
The rates of reactions are calculated under different experimental conditions.
The light intensity is measured using peroxydisulphate solution as standard
chemical actinometer. Using reaction rate and light intensity at 254 nm, the
quantum yields are calculated. The rates of photooxidation of purine bases are
found to increase with increase in [PDS] and independent of [purine]. The increase
of light intensity has been found to increase the rate of oxidation. The
quantum yields are found to depend on [purine] but independent of [PDS] and
light intensity. On the basis of experimental results a probable mechanism is
suggested in which peroxydisulphate on photolysis gives sulphate radical anion
which initiates the reaction by capturing an electron from C8 position of
purine to form purine radical cation. This radical cation deprotonates and
undergoes further oxidation to give C(8) hydroxy purine.